Explain query tree represent relational algebra expression, Database Management System

Assignment Help:

How does a query tree represent a relational algebra expression?     

Ans: This includes transforming an initial expression (tree) into an equivalent expression (tree) that is more proficient to execute. Two relational algebra expressions are said to be equal if the two expressions produce two relation of the same set of attributes and consist of the same set of tuples even though their attributes may be ordered in a different way.

 The query tree is a data structure which denotes the relational algebra expression in the query optimization process. In the query tree the leaf nodes correspond to the input relations of the query. The internal nodes denote the operators in the query. While executing the query, the system will execute an internal node operation when its operands available after that the internal node is replaced by the relation which is acquired from the preceding execution.


Related Discussions:- Explain query tree represent relational algebra expression

Differentiate between pl/sql functions and procedures, Oracle & Distributed...

Oracle & Distributed Databases 1. Differentiate between PL/SQL functions and procedures. 2. Draw the diagram of logical structure of oracle database and explain it in brief.

Explain the components of database system in details., Explain the compone...

Explain the components of Database System in details.

Define single value and multivalued attribute, Define Single Value and Mult...

Define Single Value and Multivalued attribute Single value attribute comprise a single atomic value for an entity and multivalued attribute may have much more than one value f

Define check point and its impact on data base recovery, Define check point...

Define check point and its impact on data base recovery.                  Ans:  There could be hundreds of transactions handled per minute, in a large on-line database system.

The structured query language, The Structured Query Language INTRODUCT...

The Structured Query Language INTRODUCTION Database is an organised set of information about an entity having controlled redundancy and serves numerous applications. DBMS

Define radix conversion method, Define Radix conversion method  One cle...

Define Radix conversion method  One clever way to transform binary numbers to BCD notation (binary-coded decimal) is the "double dabble algorithm". It can be adapted to transfo

What features relational dbms contribute level of integrity, A well-maintai...

A well-maintained relational DBMS has a high level of data integrity. What features of a relational DBMS contribute towards this level of integrity? Relational DBMS gives high

What is data dictionary, What is Data dictionary? A data dictionary is ...

What is Data dictionary? A data dictionary is a reserved space in a database that is employed to store information about the database itself. A data dictionary may consist o

Explain projection operation distribute over union operation, Illustrate th...

Illustrate the statement 'Projection operation distributes over the union operation'. Give an example.    Ans: Π L (E 1 ∪ E 2 ) = (Π L (E 1 )) ∪ (Π L (E 2 ))   This says th

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd